VOLCANIC DUST VEIL INDEX, NORTHERN HEMISPHERE, 1500-1969                        
 200 150 100  50   0   0   0   0   0   0                                        
   0   0   0   0   0   0   0   0   0   0                                        
   0   0   0   0   0   0   0   0   0   0                                        
   0   0   0   0   0  50  50  50   0   0                                        
   0   0   0   0   0   0   0   0   0   0                                        
   0   0   0 100 500 350 200 100   0   0                                        
   0   0   0   0   0   0   0   0   0   0                                        
   0   0   0   0   0   0   0   0   0   0                                        
   0   0   0   0   0   0 200 150 100  50                                        
   0   0   0 200 150 100  50  40  30  20                                        
  10 400 300 210 110  10  20  50  50  50                                        
  40  30  20  10 200 150 100  50   0   0                                        
   0   0   0   0   0 100  75  50  25   0                                        
   0 120  90  60  30   0  40  30 120  85                                        
 150 400 275 175  75   0  60  45  30  15                                        
 100  75  50  25   0   0   0   0   0   0                                        
 340 255 170  85 130 100  65  30   0   0                                        
   0   0 200 150 100  50   0   0   0   0                                        
 280 210 140  70   0   0   0   0   0   0                                        
   0   0   0 140 285 205 105  45   0   0                                        
   0   0   0   0   0   0   0 300 225 150                                        
  75   0  80  60  40  20   0 120  90  60                                        
  30 100  75  50  55  15  15  15  15  15                                        
 160 130  90  50   0   0   0   0   0   0                                        
   0   0   0   0  60  45  30  15   0   0                                        
   0   0 200 150 160 255 150  95  40  80                                        
 110  77  45  13   0   0   0   0   0   0                                        
   0   0  50  37  25  13   0   0   0 180                                        
 135  90  45 400 300 200 160  45  30  15                                        
   0   0   0   0   0 120 130  90  50 130                                        
  90  60  30   0   0   0   0   0   0   0                                        
   0  80 180 170 170 695 490 375 195  30                                        
  15   0 200 150 100  70  80  65  50  75                                        
  50 200 130  80  40 525 450 375 300 225                                        
 150  75   0   0   0 100 205 140  90  30                                        
   0   0   0   0   0   0 140 105  70  35                                        
   0 160 120  80  40   0   0   0 160 120                                        
  80  40   0   0   0 120  90  60  30   0                                        
   0   0   0 400 300 240 170  50 170 125                                        
  85  45  20  15  10   5   0   0  30  25                                        
  15   5 180 135  90  45   0  60  45  30                                        
  15   0  60  45  30  15   0   0   0   0                                        
   0   0   0   0   0   0   0   0   0   0                                        
   0   0   0   0   0   0   0   0   0   0                                        
   0   0   0   0   0   0   0   0   0   0                                        
   0   0   0   0   0   0   0   0   0   0                                        
   0   0   0 160 120  80  40   0   0   0                                        
